Communication devices such as UEs are enabled to communicate wirelessly in a cellular communications network or wireless communication system, sometimes also referred to as a cellular radio system or cellular networks. The communication may be performed e.g. between two UEs, between a UE and a regular telephone and/or between a UE and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the cellular communications network.
UEs may further be referred to as wireless terminals, wireless devices, mobile terminals, mobile stations, mobile telephones, cellular telephones, laptops, tablet computers or surf plates with wireless capability, just to mention some further examples. The UEs in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the RAN, with another entity, such as another user equipment or a server. The UE may also be a machine to machine communication device that serves as a data communication modem or is built in to equipment communicating data with server without human interaction.
The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area is served by an access node. A cell is the geographical area where radio coverage is provided by the access node.
The access node may further control several transmission points (TPs), e.g. having Remote Radio Units (RRUs). A cell may thus comprise one or more access nodes each controlling one or more transmission/reception points. The TP, also referred to as a transmission/reception point, is an entity that transmits and/or receives radio signals. The entity has a position in space, e.g. an antenna. An access node, also referred to as a network node, is an entity that controls one or more transmission points. The access node may e.g. be a base station such as a Radio Base Station (RBS), enhanced Node B (eNB), eNodeB, NodeB, B node, or BTS (Base Transceiver Station), depending on the technology and terminology used. The base stations may be of different classes such as e.g. macro eNodeB, micro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size.
Further, each access node may support one or several communication technologies. The access nodes communicate over the air interface operating on radio frequencies with the UEs within range of the access node. In the context of this disclosure, the expression Downlink (DL) is used for the transmission path from the base station to the mobile station. The expression Uplink (UL) is used for the transmission path in the opposite direction i.e. from the UE to the base station.
In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or even eNBs, may be directly connected to one or more core networks.
Since UEs mostly are non-stationary, non-uniformities of the system load in a wireless network may appear. Slight non-uniformities of the system load may not significantly affect the quality of provided services, however the UE's experience is likely to be impaired in more extreme cases. Among those extreme cases, a very important one is the appearance of hot spots. Herein hot spot means a small geographic portion of the coverage area heavily populated by UEs or heavily loaded by UEs with high data load, and its appearance may be due to a myriad of events usually unrelated to the communication network. If the coverage area of a TP is too heavily populated by UEs, there may not be any resources available for transmission for some of the UEs at that given transmission point.
The most advisable solution to deal with hot spots is to predict where they may appear as well as their demographic density and extent; thereafter, the prediction is availed to feed the network planning phase. A first challenge faced by this classical solution concerns designing the prediction algorithm, since any prediction attempt is usually subjected to a certain uncertainty. For the sake of simplicity, a posteriori information of the system load may be used in place of the prediction. However, this solution should be employed in a sparingly way, since it may easily lead to an over-dimensioning of the network and a clear increase in costs, since it tends to require further TPs.